Terminal Combined Update Indication for SGs Association Re-establishment
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Solution Overview
Problem
In the context of the evolved packet system (EPS), the MSC/VLR struggles to find a UE via paging during CS services when the ISR function is introduced, especially when the UE is camped on the LTE network without a supported Gs interface, leading to failed voice calls and CS services due to inability to initiate CS service paging in the EPS network.
Innovation Solution
A method is introduced where the terminal sets a combined update indication when performing location area updates, initiating a combined TA/LA Update with the MME to re-establish SGs association, ensuring timely updates and accurate judgment of association requirements, thus enabling correct CS paging and UE location even when the UE falls back to the GSM/UMTS network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal performs location area update to MSC/VLR via GERAN/UTRAN after falling back to GSM/UMTS network, then the MSC/VLR can update association information, but the terminal cannot initiate combined TA/LA Update to MME to re-establish SGs association, causing CS service paging failure
Solution Approach 1:
The terminal sets a combined update indication flag in advance when performing location area update via GERAN/UTRAN, indicating that it needs to initiate combined TA/LA Update to MME subsequently. This preliminary action ensures that the MSC/VLR can properly re-establish SGs association with MME, enabling reliable CS service paging even when the terminal falls back to GSM/UMTS network.
2Productivity
If the terminal moves to E-UTRAN from GERAN/UTRAN without setting combined update indication, then the terminal can access EPS network, but the MSC/VLR cannot find the terminal via paging during CS services
Solution Approach 1:
The terminal provides feedback information through the combined update indication flag when moving to E-UTRAN from GERAN/UTRAN. This feedback signals to the MSC/VLR that the terminal needs combined TA/LA Update to be initiated, enabling the network to properly track and locate the terminal for CS services while maintaining efficient network access.
3Adaptability or versatility
If the terminal performs separate CS and PS update/attachment procedures, then the terminal can access both CS and PS domains, but the terminal occupies separate radio resources and signaling channels, increasing system complexity
Solution Approach 1:
The patent combines CS and PS update procedures into a single combined TA/LA Update process when the terminal moves between GERAN/UTRAN and E-UTRAN. By setting the combined update indication and initiating combined update to MME, the terminal achieves both CS and PS domain access simultaneously through one procedure, reducing radio resource occupation and signaling complexity while maintaining full domain access capability.
Data Source
AI summary
A method and terminal for association update are provided. When the terminal performs location area update to a MSC/VLR via a GERAN/UTRAN, if it has performed combined update or CSFB attachment in an EPS network via E-UTRAN, then it sets a combined update indication which indicates the EPS network requires combined update when the terminal returns to the E-UTRAN from the GERAN/UTRAN; when the terminal moves to a registered tracking area of the E-UTRAN, it determines whether the combined update indication has been set or not, if yes, it initiates combined TAU and LAU to an MME. After receiving a location update request from the MME, the MSC/VLR updates stored association information and re-establishes SGs association with the MME. Accordingly, a terminal has a control module for association update, which comprises a combined update indication setting determination unit, a combined update setting unit and a combined update initiation determination unit. The present invention enables to update the SGs association in the MSC/VLR in time, thereby the MSC/VLR can always find UE through paging.